The invention concerns aqueous plastic dispersions, which are advantageously used as binding agents for paints and lacquers and also as adhesives, and are distinguished by their strong adherence, when wet, to smooth non-absorbent substrates. The invention also concerns a process for the manufacture of these dispersions and their use.
Hitherto, the use of many types of dispersion paints on smooth nonabsorbent substrates has been considerably limited on account of their poor adhesion when wet. The problem is particularly difficult when fresh painting is carried out with low-pigment dispersion paints, which, because of their high binder content, are used particularly when the paint is to be resistant to washing off.
Various proposals have been made, for example, in German Published Application Nos. DE-OS 25 35 373, DE-OS 25 35 374 and DE-OS 26 28 760, for reducing or avoiding these difficulties, which can be further increased, in particular, by the addition of flow-promoting agents, such as ethylene glycol, propylene glycol, etc. These proposals involve the inclusion by copolymerization, of vinyl acetoacetate or allyl acetoacetate or acetoacetic acid esters having the general formula: EQU R--CH.dbd.C(R)--CO--O--A--CO--CH.sub.2 --CO--CH.sub.3
in which R denotes H, CH.sub.3 -- and A denotes --(CH.sub.2).sub.1-4 --O-- or --(CH.sub.2 --CH.sub.2).sub.1-3 --O--.
The improvement so achieved is still not sufficient for many applications. There has, therefore, existed the problem of improving the adhesion, when wet, of plastic dispersions, having high wash-off resistance, suitable for the production of dispersion paints.